An apparatus has been known which acquires traveling data of a forward vehicle in order to perform vehicle control. For example, Patent Literature 1 discloses an apparatus that performs inter-vehicle communication with a forward vehicle to acquire traveling data, such as the vehicle speed, acceleration, and ID (order in a formation) of the forward vehicle, acquires the lateral displacement of the subject vehicle using a magnetic sensor provided in the subject vehicle, and performs formation traveling on the basis of the acquired information.    Patent Literature 1: Japanese Unexamined Patent Application Publication No. 09-81899